Sheet polishing machine



A ril 25, 1939. s. BLICKMAN 5,

SHEET POLISHING MACHINE v Filed May 5, 1957 2 Sheets-Sheet l INVENTOR 6au B/lc/rm m ATTORN EYS April 25, 1939. s. BLICKMAN SHEET POLISHING MACHINE Filed May 5, 1937 2 Sheets-Sheet 2 INVENTOR ATTORNEYS Patented Apr. 25, 1939 UNITED STATES PATENT OFFlCE 2 Claims.

This invention relates to a machine for polishing sheet material, such as metal sheets.

More particularly stated, the invention relates to the type of sheet polishing mechanism in which the sheet is reciprocated back and forth under polishing means, such for instance, as an endless sanding belt. The belt is driven at a high rate of speed during the polishing operation and one feature of the invention relates to the proper alinement and tensioning of the polishing belt.

Moreover, it has been found that sanding belts in polishing machines of the type described, do not give a uniform polish and finish to the sheet being polished.

For instance, such belts are not uniform in texture, especially after they have been used a short time. They have a tendency to stretch on one edge or the other which tends to cause the belt to run off the rolls.

Furthermore, the belt wears faster at the edges which causes the belt to groove the sheet at the edges. Also, slight defects in the belt out grooves in the sheet.

Another difliculty encountered is caused by a tendency of the belt to curve at the edges which also causes grooves. The sanding belt is pressed into engagement with the sheet by a rubber sur-' faced roller which is often grooved by the edges of the belt.

In machines of the type specified, the sheet is clamped to a reciprocatable belt which is automatically reversed in its travel or, in other words, travels alternately in opposite directions beneath the polishing means. The sanding belt is led around a roller having a surface of cushioning material, and the sheet being polished is pressed upwardly against the sanding belt. If the automatic reversing mechanism fails to operate, the clamp which secures the sheet to the sheet feeding belt will engage and mutilate or damage the cushioned roller.

This invention has for one of its objects to provide a sheet polishing machine of the character described with simple and practical means, operable when the machine is in operation, for properly alining and properly tensioning the sanding belt.

Another object of the invention is to provide means for oscillating the sanding belt during the operation of the polishing machine in such a manner as to overcome the tendency of the belt to cause grooves in the sheet being polished and to give a smooth, uniform polish to the sheet.

Another object of the invention is to provide a polishing machine with safety stopping means for automatically stopping the forward travel of the sheet feeding belt .or the rearward travel thereof at a predetermined limit of movement thereof in either direction.

Further objects of the invention will appear 5 from the following specification taken in connection with the drawings which form a part of this application, and in which Fig. 1 is a side elevation of a machine constructed in accordance with the invention;

Fig. 2 is a diagrammatic top plan view of the machine illustrating the wiring connections and the automatic control therefor;

Fig. 3 is a top plan view of one of the belt guiding rollers having mechanism connected there- With for alining and adjusting the roller;

Fig. 4 is an elevational view partly in section of the structure shown in Fig. 3;

Fig. 5 is a vertical sectional elevation illustrating the roller which drives the sanding belt, and a pressure roller operating in conjunction therewith to press the sheet to be polished against the sanding belt; and

Fig. 6 is a diagrammatic view illustrating the valve control mechanism for the pressure roller. 5

The invention briefly described consists of a machine comprising an endless supporting and feeding belt having means thereon for clamping thereto a sheet to be polished, means for driving said belt, mechanism for automatically reversing the drive at predetermined limits of movement of the belt in opposite directions, and safety means for automatically stopping the driving motor and operating a brake when the belt reaches a predetermined movement in either forward or reverse direction. The machine also comprises guiding rollers for a sanding belt, one of the rollers being adjustable to tension the belt and also to properly align the belt.

Furthermore, the oscillation of the adjustable roller during the operation of the machine varies the contacting engagement of the belt and sheet being polished, prevents grooves in the sheet and gives a smooth and uniform finish or polish on the sheet.

Further details of the invention will appear from the following description.

In the particular embodiment of the machine illustrated in the drawings, there is shown a sheet supporting and feeding belt In which is mounted on rolls II and I2 supported on uprights l3 and M. The belt travels back and forth over tables 15 and I6 which have mounted thereon rollers IT.

The roll l2 has a shaft 28 on which is-mounted a gear 2| which meshes with a gear 22 on a shaft 23. The shaft 23 is driven by reducing gear mechanism R from a motor shaft 24 which in turn is driven by a motor M. A brake 25, hereinafter described, is interposed between the motor M and the reducing gear R.

The wiring connections for the operation of the motor M will now be described. In the form of the invention shown, the motor is a three phase motor, the three wires being shown at A, B and C. Three switches 30, 3| and 32 are mounted in the three wires A, B and C, these switches being controlled by a solenoid S in the manner hereinafter described. The three wires A, B and C lead from the switches 39, 3| and 32 to a reversing switch 35 having a switch arm 36 which is normally maintained in neutral position by springs 31 and 38. From the reversing switch 35 the wires lead to the motor M.

The reversing switch arm 36 is connected to a slide bar suitably mounted for reciprocation and having mounted thereon a pair of limit stops 46 and 41.

The belt H] has mounted thereon a plate 48 having a clamp 49 secured thereto for clamping the metal sheet 59 to the belt. The sheet 56 when clamped to the belt is reciprocated alternately in opposite directions.

The plate 48 has secured thereto and extending beyond the ends thereof and laterally of the belt l6, a pair of lugs 5| and 52 whichtravel with the belt. The lug 52 is adapted to engage the stop members 46 and 41 at predetermined points in the forward and reverse travel of the belt. When the lug 52 engages the stop member 46 the bar 45 and the reversing switch control arm 36 are moved forwardly and the reversing switch operates in the usual well known manner to reverse the direction of drive of the motor M. 'It will be understood that suitable relays are operated by the reversing switch to effect this motor reversing operation. As soon as the belt starts its reverse travel the lug 52 will leave the stop, member 46 and the bar 45 will be returned to its neutral or intermediate position by the spring 38. When the belt reaches its predetermined limit of reverse travel the lug 52 will engage the stop member 41 and operate the reversing switch to again reverse the motor and drive the belt in the forward direction.

In order to prevent an over-travel of the belt in either direction in'the event that the reversing mechanism fails to operate, the lug 5| is mounted to engage the switch arms 4| or 43 of the switches '40 or 42. When the lug 5| engages either one of these switch arms the circuit of the solenoid S will be opened, thus causing the switches36, 3| and 32 to open and breaking the motor circuit.

The brake 25 is provided for braking the drive of the motor shaft when the motor circuit is opened. This brake is constructed in the usual well 'known manner and is connected by wires D and E to the wires A and B. This brake circuit is normally closed, thus holding the brake in inoperative position. However, when the brake .cii cuitis-opened upon opening of one of the switches 48 or 42, a spring will cause the brake to be ap. plied to the motor shaft 24, thus stopping the rotation thereof.

The polishing mechanism utilized in the machine illustrated in the drawings consists of an endless sanding belt 55 which is mounted on three rollers 55, 51 and 58. The roller 51 is the driving roller and has a surface of cushioning material. Roller 56, however, may be used as the driving roller. In order to press the sheet being p01- ished against the sanding belt a pressure roller 69 is mounted below the cushion roller 51 and below the belt |8. The pressure roller is mounted in journal boxes 6| and 62 which are vertically slidable in brackets 63 and 64. Each journal box has extending downwardly therefrom a plunger or rod 65 which is secured at its lower end to a diaphragm 65 mounted in a dash pot 51. Ihe dash pot has connected thereto a pair of pipes 68 and 69, the pipe 68 leading into the upper part of the dash pot above the diaphragm 66, and the pipe '59 leading into the lower part of the dash pot below the diaphragm 66. The diaphragm 66 is flexibly mounted and is adapted to move upwardly or downwardly, depending on the pressure applied to the dash pot.

The pressure in the dash pot is controlled by a valve 18, shown diagrammatically in Fig.6. Ihe valve casing has a pressure inlet pipe 1| and exhaust outlet pipes 12 and 13. When the valve is adjusted to the position shown in the upper portion of Fig. 6 the pressure pipe 1| is connected to the pipe 69 and pressure is applied to the lower end of the dash pot, thus forcing the plunger 65 upwardly and pressing the pressure roller 68 in an upward direction to press the sheet being polished against the sanding belt 55. In this position of adjustment of the valve 79 the upper pipe 68 is connected to the exhaust 12.

In the lower portion of Fig. 6 the valve is shown in its other position of adjustment in which the pressure pipe 1| is connected to the pipe 68 and the pipe 69 is connected to the exhaust pipe 13. In this position of adjustment of the valve the pressure roller 68 will be forced downwardly.

The valve 19 is manually controlled and pressure is applied to and released from the roller as desired.

In order to properly align and tension thesanding belt 55 the roller 58 is mounted for adjustment about a vertical axis, preferably passing through the center of the roller, and is also mounted for adjustment toward and away from the roller 56 to properly tension the belt.

The roller 58 is mounted in bearings 15 and 16 carried by brackets 11 and 18 which in turn are mounted on a base frame or plate 19. The frame or plate 19 has secured to the central portion thereof and extending therebelow a circular block 88 which is rotatably mounted in a frame 8|. The frame 8| has extending upwardly from the ends thereof flanges 82 and 83 which are provided with arcuate surfaces-84 which coact with arcuate end surfaces on the plate 19. The arcuate surfaces are formed on radii having for their center the center of the circular block 8|],

In order to adjust the roller 58 about the axis of the block 8|], an arcuate rack 85 is secured to one end of the base frame 19 and is engaged by a worm .86 mounted on a shaft 81 having also secured thereto a bevel gear 88. The gear 881s rotatable by a bevel gear 89 which meshes therewith and is mounted on a shaft .90 manually 'ro- As the handle 9| is rotated in one direction or the other, the roller 58 will be swung about a vertical axis, passing through the vertical center of the roller and will thus be properly centered.

The frame 8| and the plate or base frame I9 carried thereby are supported on a fixed base 95 and are adjustable on the base to properly tension the belt 55, This adjustment is accomplished by means of a pair of screws 96 and 91 which extend through and are threaded in the end portions of the frame 8 I. Each of these screws has mounted on the end thereof a worm 98 which engages a worm gear 99 mounted on a shaft I having a handle I0l secured to one end thereof.

As the shaft I00 is rotated the screws 96 and 9! will be rotated, thus moving the frames I9 and 8| and the roller 58 in one direction or the other to tighten or loosen the belt, depending on the direction of rotation of the handle IOI carried by the shaft I00.

The fixed base 95 is mounted on pedestals or stanchions I02.

The roller 51, the pressure roller 60, commonly called a billy roll, the dash pots and operating connections therefor are all mounted on stanchions or pedestals I03. The roller 56 is supported on stanchions I04.

Operation The machine operates as follows: The sanding belt 55 is continuously driven during the operation of the machine and the manually controlled valve 10 controls the pressure of the sheet being polished against the sanding belt. The belt I0 which supports and feeds the sheet being polished travels alternately in opposite directions, the direction of travel being automatically reversed at predetermined limits of the forward and reverse travel by the engagement of the lug 52 with the stop members 46 and 4'! which operate the reversing switch and automatically reverse the motor,

However, should the reversing mechanism fail to operate, the lug 5| will engage one of the switch arms 4| or 43, thus opening the circuit of the solenoid S and thereby opening the switches 30, 3| and 32 which lead to the motor. At the same time the circuit for the brake 25 will open and the brake spring will operate to apply the brake to the motor shaft 24 and instantaneously stop the rotation thereof. 1

The belt 55 operates at a high rate of speed an the belt can be properly aligned by the operation of the handle 9| which adjusts the roller 58 about a vertical axis passing through the vertical center thereof. Furthermore, the proper tension on the belt 55 can be applied by manipulating the handle I0! which adjusts the roller 58 toward or away from the roller 56,

From the foregoing description it will be clear that a simple, practical and efficient polishing machine has been designed and that the machine can be so adjusted as to properly align and tension the sanding belt and, furthermore, the supplemental safety stop mechanism will effectively prevent an over-travel in either direction of the belt in the event of the failure of the reversing mechanism to operate. Thus, damage to or mutilation of the cushion roll 51 is effectively prevented.

Although one specific embodiment of the invention has been particularly shown and described, it will be understood that the invention is capable of modification and that changes in the construction and in the arrangement of the various cooperating parts may be made without departing from the spirit or scope of the invention, as expressed in the following claims.

What I claim is:

l. A sheet polishing machine comprising an endless sheet supporting and feeding belt, means for clamping a sheet to be polished to said belt, means including an electric motor for driving said belt, means for reversing the motor and reversing the travel of the sheet supporting belt at predetermined limits of forward and reverse travel thereof, polishing means engageable with the sheet during the travel thereof, and means including switches and control members carried by the belt for automatically stopping the motor when the belt reaches predetermined limits in the travel thereof.

2. A sheet polishing machine comprising an endless sheet supporting and feeding belt, means for clamping a sheet to be polished to said belt, means including an electric motor for driving said belt, means for reversing the motor and reversing the travel of the sheet supporting belt at predetermined limits of forward and reverse travel thereof, polishing means engageable with the sheet during the travel thereof, means including switches and control members carried by the belt for automatically stopping the motor when the belt reaches predetermined limits in the travel thereof, and brake means controlled by said switches whereby the brake is operated when the switches are actuated by the switch control members.

SAUL BLICKMAN. 

